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At least 19 recordsLinked to original sources
PubMed2001

Influence of scan radius correction for ocular magnification and relationship between scan radius with retinal nerve fiber layer thickness measured by optical coherence tomography.

PURPOSE: To investigate how optical coherence tomography (OCT) modifies the preset scan parameters to correct the errors resulting from ocular magnification, the influence of examiner's final correction of those already modified parameters on retinal nerve fiber layer (RNFL) thickness measurements, the induced change on RNFL thickness measurements and RNFL estimated integrals (RNFL(estimated integrals)) by adjusting the actual scan radius during RNFL examinations performed by OCT. METHODS: Thirty-five healthy patients underwent an RNFL examination by OCT four times using different scan radii. The first scan was performed with the preset circular scan diameter of 3.46 mm; the actual scan diameter was different, however, because it was modified by the OCT instrument. The second, third, and fourth scans were generated after readjusting the already modified scan diameter by the examiner to 3.46, 3.20, and 3.60 mm. The relationship of axial length and refractive error with the actual scan radius (with ocular magnification calculated by OCT), with the influence of the examiner's final correction on RNFL thickness measurements, with the relationship between scan radius with RNFL thickness measurements, and with RNFL(estimated integrals) were investigated. RESULTS: The actual scan diameter was found to be primarily determined by axial length (R = 0.97, P < 0.0001), but the influence of refractive error was small (R = -0.26, P = 0.067). Final correction of the actual scan radius by the examiner had a significant influence on RNFL thickness measurements (P = 0.025). RNFL thickness measurements obtained without correction of the actual scan radius for magnification were found to be inversely correlated with axial length (R = -0.54, P = 0.001), whereas no similar relationship was found when RNFL thickness measurements were obtained with correction (R = 0.21, P = 0.11). A reciprocal relationship between 1/scan radius with RNFL thickness measurements (they tended to be thinner as scan radii were increased) was found (R = 0.41, P = 0.169), but RNFL(estimated integrals) areas were found to be independent of the scan radius (P = 0.521). CONCLUSION: To increase the accuracy of RNFL thickness measurements, it will be appropriate for the examiner to manually correct the actual scan parameters to the desired or preset ones after their automatic modification performed by the OCT instrument. Keeping the actual scan radius constant for repeated exams is also recommended because RNFL thickness measurements were found to depend on scan size. Alternatively, RNFL(estimated integrals) could be used because they were found to be independent of the scan size.

Adolescent↗
PubMed1977

Asynchronous growth of the canine radius and ulna: effects of cross pinning the radius to the ulna.

Kirschner wires were introduced into the diaphyseal region of the radius and the ulna in 4 Australian shepherd crossbred pups, and change in relationships between the bones during growth was demonstrated. The contributions to longitudinal growth of the radius from proximal and distal growth plates were also calculated. Over the period of growth, the proximal growth plate contributed approximately 40% of the length of the radius. A marked shifting of the radius in relationship with the ulna occurred. This normal shifting between radius and ulna was prevented in 6 dogs by cross pinning the radius to the ulna at 90, 111, 142, and 168 days of age. Marked change was produced in the elbow joint, where altered relationships of articular surfaces of the radius and the ulna resulted in displacement of the humeral condyle from the trochlear notch of the ulna. Changes in dogs cross pinned at 90 and 111 days of age were most severe and consisted of severe degenerative changes which were most marked on the lateral side of the distal half of the trochlear notch of the ulna.

Aging↗
PubMed2004

Limited diagnostic agreement of quantitative sonography of the radius and phalanges with dual-energy x-ray absorptiometry of the spine, femur, and radius for diagnosis of osteoporosis.

OBJECTIVE: The aim of our study was to evaluate the diagnostic agreement of quantitative sonography of the radius and proximal phalanx and dual-energy X-ray absorptiometry (DXA) of the radius, lumbar spine, and femoral neck for the detection of osteoporosis. MATERIALS AND METHODS: In 95 women (mean age, 53 +/- 13 years) and 26 men (mean age, 53 +/- 13 years), DXA measurements of the lumbar spine (posterior-anterior, L1-L4) and the femoral neck, as well as quantitative sonography of the radius and proximal phalanx of the third finger were obtained. The percentage of patients below a given threshold was calculated for each imaging technique. A T score of less than -2.5 indicated presence of osteoporosis. Diagnostic agreement in identifying individuals with osteoporosis was assessed using kappa scores. RESULTS: Between 14% and 22% of the patients were classified as osteoporotic after DXA of the various regions of interest of the radius, 31% after DXA of the spine, 43% after DXA of the femoral neck, 32% after quantitative sonography of the distal radius, and 34% after quantitative sonography of the phalanx of the third finger. Correlation coefficients between T values for quantitative sonography and those for DXA varied between not significant and 0.54 at the different regions. Kappa analysis showed the diagnostic agreement among quantitative sonography and DXA to be fair to moderate (kappa = 0.38-0.48). The highest agreement was between quantitative sonography of the proximal phalanx of the third finger and DXA of the total radius (kappa 0.48; p < 0.05). CONCLUSION: Considerable diagnostic disagreement exists between quantitative sonography and DXA of the forearm, as is true for most quantitative techniques in the assessment of skeletal status. The lack of correlation makes quantitative sonography impractical for routine diagnostic use but might characterize different parameters related to bone quality.

Absorptiometry, Photon↗
PubMed1990

Electrode radius predicts lesion radius during radiofrequency energy heating. Validation of a proposed thermodynamic model.

Myocardial heating by transcatheter delivery of radiofrequency (RF) energy has been proposed as an effective means of arrhythmia ablation. A thermodynamic model describing the radial temperature gradient at steady state during RF-induced heating is proposed. If one assumes that RF power output is adjusted to maintain a constant electrode-tissue interface temperature at all times, then this thermodynamic model predicts that the radius of the RF-induced lesion will be directly proportional to the electrode radius. A total of 76 RF-induced lesions were created in a model of isolated canine right ventricular free wall perfused and superfused with oxygenated Krebs-Henseleit buffer. Electrode radius was varied between 0.75 and 2.25 mm. RF energy (500 kHz) was delivered for 90 seconds, and the power output was adjusted to maintain a constant electrode-tissue interface temperature of 60 degrees C. A strong linear correlation was observed between electrode radius and lesion radius in two dimensions: transverse (p = 0.0001, r = 0.85) and transmural (p = 0.0001, r = 0.89). With these data, the temperature correlation with irreversible myocardial injury in this model was calculated at 46.6-48.8 degrees C. Therefore, the proposed thermodynamic model closely predicts the observed relation between electrode radius and lesion size during RF myocardial heating.

Animals↗
PubMed2003

Fixation of distal radius fractures using AO titanium volar distal radius plate.

This study is to assess the effectiveness and outcome of the AO titanium volar distal radius plate (Synthes) in the treatment of peri-articular volar rim fractures of the distal radius. It was conducted on 22 patients with distal radius fractures who underwent open reduction, internal fixation using the AO titanium volar distal radius plate between July 1998 and December 1999 at the Changi General Hospital. The radiographs of the patients were analysed upon fracture union and assessment of wrist function was done using Gartland and Werley criteria. There were four extra-articular AO Type A2(1) and A3(3): the remaining 18 intra-articular fractures consisted of AO B3(2), AO C1(11), AO C2(2) and AO C3(3). The average follow-up period was 12.6 months (range 7-23). Radiological review showed bone healing in 21 patients (95.5%) and good articular congruity for all intra-articular fractures with less than 2 mm step-off. Three patients defaulted follow-up. Complications were few with one wound infection, one tendon rupture and three neuropraxia of the superficial radial nerve. Wrist function was excellent in three patients, good in 12 and fair in four. The AO titanium plate with its distal buttressing ability is an effective treatment modality in patients with distal radius fractures involving the peri-articular volar rim.

Adult↗
PubMed1979

Asynchronous growth of the canine radius and ulna: effects of retardation of longitudinal growth of the radius.

After 2,000 rads of x-radiation to the right distal radial physis of eight 70-day-old dogs, the longitudinal growth of the right radius was retarded 42.1% when compared with the growth of the nonirradiated left radius. Asynchronous growth of the right radius and ulna resulted. The gross and radiographic changes that occurred over the subsequent 75 days were described. Subluxation of the humeroradial and humeroulnar joints occurred and was first observed 31 days after irradiation. By 75 days after irradiation, the radius was puller 7.8 mm distally by the radioulnar ligament. However, subluxation of the humeroradial joint was minimized by accelerated growth from the proximal radial physis and articular cartilage. Acceleration of growth also occurred at the distal radial articular cartilage. Growth from the distal ulnar physis and styloid process was retarded. It was thus apparent that after retardation of growth from the distal radial physis, considerable adjustment occurred in the relationship between the radius and the ulna and also in growth from their other physes, which reduced the deleterious effects of the growth retardation.

Animals↗
PubMed1989

Osteosynthesis of the radius by double elastic spring-pinning. Functional treatment of the distal end fractures of the radius. A study of 130 cases.

The insertion of two elastic spring-pins in the marrow cavity of the radius gives automatically setting of the radius distal extremity's fracture. The stabilization so obtained is enough to avoid any kind of plaster immobilization. This quick and simple intervention was systematically practised during a two year period for all fractures of the lower-end of the radius. The pins are introduced directly through the skin without the need for incision. Patients are encouraged to undertake their normal activities immediately after the operation. The operation technic is described in detail in the following article. The study performed on 130 fractures observed and recorded in detail allows the analyses of the complications encountered, results obtained and the definition of indications as well as the method's limitations. Good and excellent anatomical results were obtained in 71%. Good and excellent functional results were obtained in 74% of the cases after the 6th week and, as high as 92%, after the 12th week. The majority of the negative anatomical results obtained only pertains to poor alignment of the radius's front wall. At the present time, this poor alignment must be stabilized and corrected by the introduction of a third anterior pin.

Adolescent↗
PubMed2006

[Open reduction and internal fixation of distal radius extension fractures in women over 60 years of age with the dorsal radius plate (pi-plate)].

PURPOSE: The goal of this study was to review the clinical and radiological results and to correlate them with the functional outcome score DASH in women over 60 years who underwent open reduction and internal fixation with a pi-plate for displaced distal radius fractures. METHOD AND CLINICAL MATERIAL: In this retrospective study, forty-nine women over 60 years old with mainly intra-articular distal radius fractures underwent open reduction and internal fixation with a pi-plate. The dorsal approach was used permitting an anatomical reduction of the articular surface under direct vision of the radio-carpal joint. Patient follow-up was for a minimum of twelve months with a mean of 32 months. RESULTS: For 71 % of patients, there were no limitations in their daily activities and only one patient complained of a major disability. Overall, the flexion of the wrist was reduced by 15 degrees compared to the opposite side (mean 50 degrees). The DASH score (14.4) was not higher than that of a comparable age controlled group without radius fracture. The pi-plate was demonstrated to be a stable implant in osteoporotic bone and there was only one secondary dislocation. Most patients were painfree with two patients describing tolerable pain, one because of a progressing radio-carpal osteoarthritis and the second due to a neuroma of the superficial branch of the radial nerve. The other major complication was a late rupture of the extensor tendon of the index finger in one of the twelve patients where the pi-plate had not been removed. CONCLUSION: We recommend anatomical reduction and internal fixation for displaced intra-articular distal radius fractures using a dorsal approach to achieve a good wrist function including painless load bearing with the implant removed four months after surgery.

Aged↗
PubMed1999

Bone mineral density in the distal radius in a healthy Japanese population and in relation to fractures of the distal radius.

Changes in bone mineral density with age were measured in the distal radius of healthy adults using dual energy X-ray absorptiometry. A total of 2789 healthy women (20-95 years old) and 1255 healthy men (20-87 years old), and 72 women (52-94 years old) and 23 men (51-79 years old) with fractures of the distal radius were assessed. Bone mineral density remains relatively stable in men despite aging, and was significantly higher than in women in every decade. In women aged 70 years and more, the bone mineral density was significantly lower in the fracture group than the non-fracture group. In men with fractures of the distal radius, there were no significant differences between bone mineral density and age. In the fracture groups loss of radial inclination after reduction correlated with decreased bone mineral density, but there was no significant regression between bone mineral density and the decrease in radial length or palmar tilt.

Adult↗
PubMed2003

[Angularly stable radius plate: progress in treatment of problematic distal radius fracture?].

Fractures of the distal radius represent one of the most common fractures and have high socioeconomic relevance. Using the volar approach to avoid the soft tissue problems associated with dorsal plating, we treated a consecutive series of 49 displaced intra-articular distal radius fractures with a new fixed-angle internal fixation device. According to the AO classification, there were 21 C1, 19 C2, and nine C3 fractures. A retrospective study was carried out to obtain the functional results after open reduction and plate osteosynthesis. Loss of correction between postoperative and follow-up radiography was 1 degrees in volar tilt and radial inclination. The radial shortening was 1 mm. Wrist motion at final follow-up examination had recovered to an average of 80% of that at the normal, contralateral site. Overall outcome according to the Gartland and Werley scales showed 35% excellent, 50% good, and 15% fair results. Using the Martini score, we obtained 85% excellent and good results. The DASH score represented high subjective satisfaction.

Adult↗
PubMed1986

Body segment mass, radius and radius of gyration proportions of children.

The segment inertial parameters of children are fundamental to the analysis and simulation of their movements. Generally it has been recognized that adult parameters cannot be extrapolated and most of the anthropometric data on children are of little or no use for determining inertias. Consequently, there have been few studies of children's kinetics. In response to this problem a longitudinal investigation, the Laurentian Study of Biomechanical Development, was launched and in this paper the effects of growth on selected segmental size and inertial parameters are reported for boys between the ages of 4 and 15 yr. The twelve subjects, representing heterogeneous body types were followed over 3 yr for a total of 36 observations. Elliptical zones 2 cm wide were used to model the body and segment inertias calculated using segment densities from the literature. These inertias were the mass, moment of inertia and mass centroid location for a fourteen segment planar representation of the body. The general accuracy mean error based on body mass was 0.203% which is consistent with reports from similar studies and techniques. Plots of segment mass proportions with respect to age showed a decrease in the head proportion balanced by increases in the thigh, shank, foot and upper arm proportions in particular. The trends for each segment were consistent with the trends for linear measures reported in the anthropometry literature. Radius proportions to the mass centroid and radius of gyration proportions were also plotted and showed smaller but consistent changes with respect to age. Linear regressions were then fitted to the distributions and standard errors calculated. The magnitude and slope of the regressions were for the most part consistent with a reported cross-sectional study of Japanese children. Where data were available, predicted parameters were compared with the reported parameters for a 12 yr old analyzed using a different mathematical model. Comparisons were also made between the predicted parameters at 15 yr and the reported parameters for healthy young adults who had been scanned using a gamma-radiation technique. For most parameters there was either good agreement or differences could be explained logically. The traditionally used parameters from older cadavers were quite inconsistent with the above. The variances of the 36 observations about the regression lines as indicated by the standard errors were small. As an illustration of the effect of these variances, the trunk parameters for a 10 yr old performing a standing jump for distance were decreased by 1 S.E. and this matched by increases for the thigh, shank and head.(ABSTRACT TRUNCATED AT 400 WORDS)

Age Factors↗
PubMed2000

Open reduction and internal fixation of intra articular and unstable fractures of the distal radius using the AO distal radius plate.

This study reports the results of open reduction and internal fixation of 25 dorsally displaced distal radial fractures using a specifically designed plate for the distal radius, the AO pi plate (Synthes Ltd, Paoli, USA). Twenty-one of these fractures were complex and intra-articular (AO Type 'C'). Measurement of range of motion of the affected wrist at an average follow-up of 16 months revealed a median return of 60 degrees of wrist extension, 40 degrees of wrist flexion, 90 degrees of pronation and 90 degrees of supination. Radiographic assessment revealed restoration of normal radial length, inclination and palmar tilt in all but six cases. The final outcome, as assessed by the Gartland and Werley scale, was excellent in four cases, good in 11, and fair in ten cases. Complications were seen in five patients.

Adolescent↗
PubMedDate not supplied

Three epiphyseal fractures (distal radius and ulna and proximal radius) and a diaphyseal ulnar fracture in a seven-year-old child's forearm.

SUMMARY: The authors report a rare case of fracture separations at both ends of the radius combined with an epiphyseal and diaphyseal fracture of the ipsilateral ulna. A seven-year-old girl fell one story and sustained a closed injury of her forearm. A closed reduction was unsuccessful, and an open reduction was performed with three of the four fractures being secured with Kirschner wires. These wires were removed one month later, and range-of-motion exercises were started. Thirty months after surgery, both forearms were equal in length, although the proximal radial epiphyseal line appeared partially closed. Joint motions, including forearm rotation, were normal. Radiologically, the ulnar diaphysis and the radial neck were posteriorly convex 20 degrees and 18 degrees, respectively.

Child↗